We analyze the electricity transmission planning process in Germany (Netzentwicklungsplan), which separates transmission expansion decisions from generation dispatch. We employ an economic modeling approach to analyze two different network planning settings. In the first setting, there is no trade-off between transmission network development and generation dispatch, as is currently the case in Germany. A second setting alternatively allows for such a trade-off, and thus represents a welfare superior way of transmission network planning. Applications with the two model variants are carried out for the German electricity system in 2035. The results illustrate overinvestment in transmission capacity and decreased welfare associated with the Netzentwicklungsplan.